1. Field of the Invention
The present invention relates to the repair of vascular and venous vessels in the body, and, more particularly, to the capture of debris that may result from such repair. As an unwanted result, emboli or clots may flow from the treatment site. Hazards may occur when, as a result of such repair activity, debris flows downstream from the repair to produce stenosis which disrupts flow. Such debris may result in stroke in the case of cerebral vascular treatment or myocardial infarct in the case of coronary vascular treatment. More particularly, the present invention relates to vascular procedures, which involves flattening or fracturing an accumulation of plaque in a blood vessel in order to reduce a blockage that has resulted from the accumulation. Angioplasty, for example, may treat blockages in coronary, leg and carotid arteries.
2. The Prior Art
A number of implantable devices have been used to capture particles dislodged into blood vessels. Because of their size, however, these devices have not been readily adaptable for smaller vessels in major organs. Also, often being surgically implanted, they are difficult to place and remove. In some cases they become a permanent prosthesis. Such devices are disclosed in Mobin-Uddin U.S. Pat. Nos. 3,540,431 and 4,727,873. Kimmel, Jr. U.S. Pat. No. 3,952.747, Simon U.S. Pat. No. 4,425,908, Gianturco U.S. Pat. No. 4,494,531, Molgaard Neilsen U.S. Pat. No. 4,619246, Metals U.S. Pat. No. 4,688,533, Palmaz U.S. Pat. No. 4,793,348, and Palestrant U.S. Pat. No. 4,832,055. A disclosure is made of a filter device in Wholey et al. U.S. Pat. No. 4,723,549, but the device, being part of the catheter, does not allow separate procedures using different catheters to take place without removing the filter device. Similarly other devices, such as Clark U.S. Pat. No. 3,996,938. Roger et al U.S. Pat. No. 5,160,342, and Luther U.S. Pat. No. 4,650,466, disclose devices that are part of the catheter. Bates et.al. U.S. Pat. No. 5,658,296 discloses a catheter that allows a catching mesh that is unattached to a guide wire so that it remains stationary when and if the guide wire is moved. Rasmussen et.al. U.S. Pat. No. 5,133,733 describes a mesh and shroud arrangement that is not removable and replaceable. Daniel et.al. U.S. Pat. No. 5,814,064 describes a catching device on the distal end of the guide wire, which is not contained in a capsule and is not controlled by shrouds. None of these prior art devices can cooperate in effectively controlling a stent.
It is desired to provide a greatly improved debris and emboli protection device that maintains its intended configuration in both high and low pressure fluid environments without interfering with interventional repairs, that has a sufficiently small profile for compatibility with small blood vessels such as the coronary or carotid arteries, and that can easily and safely be removed with the captured debris and emboli following intervention.
The present invention contemplates a system and process for capturing debris during angioplasty or the like, wherein a catheter is threaded through a proximal incision into an artery or other vessel and thence to a distal location therewithin, at which treatment is to be administered. The catheter comprises an outer holding sheath, an intermediate deployment sheath, and an inner guide wire, all of which are reciprocable with respect to each other. At the distal end of the deployment sheath is a structural ring. At the distal extremity of the guide wire is a surgical capsule, which is retained within the free end of the deployment sheath before use and is extended through the structural ring from the free end of the deployment sheath when in use. The surgical capsule includes a rearward hub that is affixed to the guide wire, a plurality of shrouds in the form of outwardly biased leaf-springs that have rearward extremities affixed to the hub and that extend forwardly from the hub, an elastomeric ring that is affixed to the forward ends of the shrouds, and a mesh cap having a rim that is affixed to the elastomeric ring. The arrangement is such that: when the capsule is un-deployed, i.e. when the capsule is withdrawn into the deployment sheath by the guide wire, the free ends of the shrouds and the rim of the mesh cap are constricted by the inner wall of the deployment sheath; and when the capsule is deployed, i.e. when the capsule is extended from the deployment sheath by the guide wire, the free ends of the shrouds and the rim of the mesh cap are spring pressed by the shrouds into contact with the wall of the blood vessel into which the catheter has been inserted.